Supernova 2016iet is an example of one of the most extreme types of stellar explosions, though it has some odd features. (Credit: Gemini Observatory/NSF/AURA/ illustration by Joy Pollard)

In November of 2016, the sharp-eyed Gaia spacecraft spied a supernova that exploded some billion light-years from Earth. Astronomers followed up with more telescopes, and quickly realized that this supernova – dubbed SN2016iet – was an odd one in many ways.

For one, the star that caused the supernova se